Werth's first home run of the season was a doozy, a go-ahead grand slam in the eighth inning Wednesday night to lift the Washington Nationals to a thrilling 10-7 win over the Marlins.

Werth flung his bat after cracking Carlos Marmol's second pitch, a 94 mph fastball, into the visitors bullpen to give him five RBI on the night.

"The ball stayed a little in the middle and he hit it good," Marmol said.

The Nationals climbed out of an early 5-0 hole after the Marlins roughed up Jordan Zimmermann, knocking the right-hander out after 1 2/3 innings.

They won the opener of the three-game series 5-0 on Tuesday and will go for their second sweep of the season on Thursday.

Bryce Harper also got his first home run of the season, a three-run blast in fourth inning that chased Miami righty Brad Hand.

Derek Dietrich and Jarrod Saltalamacchia homered for the Marlins, who have dropped three in a row.

There were three umpire reviews in the game -- on Dietrich and Harper's home runs and a play at the plate -- and the game lasted nearly four hours despite going just 8 1/2 innings.

It looked like it would be over early after Zimmermann gave up five runs and seven hits in 1 2/3 innings in the shortest outing of his career. His ERA climbed to 8.10.

"He just struggled with his command and they came out swinging," said Nats manager Matt Williams. "They were really aggressive and he wasn't crisp with his command."

Craig Stammen threw 3 1/3 scoreless innings in relief of Zimmermann and Tyler Clippard (1-1) got the win despite giving up a go-ahead run in the eighth inning on Garrett Jones' double. Werth started the relay throw from right field that got Giancarlo Stanton at the plate on a play that was upheld on review.

Hand gave up four hits for Washington in his first start of the season -- three of them in the fourth inning, including Harper's blast. He struck out four and walked two in his 3 1/3 frames.

Marlins leadoff hitter Christian Yelich was a tough out all night, going 3- for-4 with two walks, three runs scored and an RBI single. Adeiny Hechavarria added two hits, including a triple.

Harper homered at the end of a 10-pitch at-bat in the fourth inning on a 94 mph fastball he ripped into the upper deck over the right-field pole.

The blast was upheld after the second replay review of the game and drew the Nationals within 5-3.

After the Nationals took a 6-5 lead, Saltalamacchia stroked Drew Storen's third pitch over the wall in center field leading off the seventh inning to tie the score at 6-6.

Game Notes

Marmol (0-1) pitched one inning ... Rafael Soriano pitched the ninth for his second save ... The Nationals are 6-2 this season, all against fellow NL East teams. They are 16-5 against the Marlins since the start of last season ... Harper homered for the first time since last Sept. 19 against Miami. His previous homer was also against the Marlins, on Aug. 29 ... Jacob Turner was slated to start for Miami but was scratched after suffering a right shoulder injury in the batting cage.